1. Field of the Invention
The present invention concerns a catalyst that can be used in various fields including catalytic oxidation, as well as deodorization or ozone decomposition and, in particular, it relates to a catalyst capable of improving its catalytic function by applying indirect electric heating to the catalyst itself thereby elevating the catalyst temperature. The present invention also relates to a useful method of using such a catalyst.
2. Description of the Prior Art
When a catalyst, e.g, for catalytic oxidation is used, the catalyst is heated generally in view of the reaction temperature. However, heating of the catalyst requires an additional installation of a heating source such as a gas burner or an electric heater. This is not only economically disadvantageous in view of the installation cost but also results in a drawback in view of a heat efficiency since heating by the heating source is usually applied by indirect heating. Further, since a space for the heating source has to be secured, no compact structure can be attained. In addition, indirect heating of the catalyst as described above leads to the loss of heat energy, as well as it inevitably brings about unevenness in the heating.
On the other hand, a catalyst for ozone decomposition or a catalyst for ozone deodorization is usually operated at a normal temperature without heating but the catalytic function can not fully be utilized sometimes depending on the working conditions. For instance, the catalyst activity can not fully be attained due to the effect of moisture if an object to be treated is a gas at high humidity. It is considered that the active sites at the surface of the catalyst are covered with moisture to reduce the chance of contact between the gas to be treated and the catalyst. Accordingly, it is difficult to maintain the catalyst set to a reaction device at a high catalytic activity for a long period of time in such a case. For avoiding such a disadvantage, there may be considered to pass a gas at high humidity into the reaction device after previously heating the gas, but this requires installation of an additional heating source to bring about a problem similar to that in the catalyst used for catalytic oxidation.